Effect of antagonist muscle fatigue on knee extension torque

M. Beltman, A. J. Sargeant, Derek Ball, C. N. Maganaris, A. De Haan

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The effect of hamstring fatigue on knee extension torque was examined at different knee angles for seven male subjects. Before and after a dynamic flexion fatigue protocol (180degrees s(-1), until dynamic torque had declined by 50%), maximal voluntary contraction extension torque was measured at four knee flexion angles (90degrees, 70degrees, 50degrees and 30degrees). Maximal torque generating capacity and voluntary activation of the quadriceps muscle were determined using electrical stimulation. Average rectified EMG of the biceps femoris was determined. Mean dynamic flexion torque declined by 48+/-11%. Extensor maximal voluntary contraction torque, maximal torque generating capacity, voluntary activation and average rectified EMG at the four knee angles were unaffected by the hamstring fatigue protocol. Only at 50degrees knee angle was voluntary activation significantly lower (15.7%) after fatigue (P<0.05). In addition, average rectified EMG before fatigue was not significantly influenced by knee angle. It was concluded that a fatigued hamstring muscle did not increase the maximal voluntary contraction extension torque and knee angle did not change coactivation. Three possible mechanisms may explain the results: a potential difference in recruited fibre populations in antagonist activity compared with the fibres which were fatigued in the protocol, a smaller loss in isometric torque generating capacity of the hamstring muscle than was expected from the dynamic measurements and/or a reduction in voluntary activation.

Original languageEnglish
Pages (from-to)735-741
Number of pages6
JournalPflugers Archiv : European Journal of Physiology
Volume446
DOIs
Publication statusPublished - 2003

Keywords

  • biceps femoris
  • coactivation
  • electrical stimulation
  • EMG
  • isometric and isokinetic contractions
  • ANTERIOR CRUCIATE LIGAMENT
  • ISOKINETIC EXERCISE
  • COACTIVATION PATTERNS
  • JOINT FORCES
  • QUADRICEPS
  • HAMSTRINGS
  • CONTRACTION
  • STRAIN
  • MUSCULATURE
  • STABILITY

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